Motor-drive for sewing-machines



H. MAIMIN.

MOTOR DRIVE FOR SEWING MACHINES.

APPLICATION FILED DEC-8, I919. 1,377,018.

Patented May 3, 1921.

2 SHEETS-SHEET 1.

lrromaqs H. MAIMIN.

MOTOR DRIVE FOR SEWING MACHINES.

APPLICATION FILED DEC-8. 1919.

1,377,018. v Patented May 3,1921.

2 SHEETS-SHEET 2.

3 vwc ntoz ZMIC, ekjjm mt/JAB PAT HYIAN MAIMIN, OF NEW YORK, N. Y.

MOTOR-DRIVE FOR SEWING-MACHINES.

Specification of Letters Patent.

Patented May 3, 1921.

Application filed December 8, 1919. Serial No. 343,216.

To all whom it may concern:

Be it known that I, HYMANMAIMIN a citizen of the United States, residingat New York cit in the county of New York, State of New ork, haveinvented certain new and useful Improvements in Motor-Drives forSewing-Machines; and I do hereby declare the following to be a full,clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame.

This invention relates to motor drives for sewing machines.

Sewing machines, particularly those that are to be used continuously,are usually driven by a small electric motor mounted on the frame ortable of the machine and connected in permanent operative relation tothe driving wheel of the machine by means of a belt or by a frictionpinion which is pressed against the driving wheel by a spring. Themotors are usually provided with rheostats for preventing a sudden rushof current when the motor is started under load, and also to permit thespeed of the machine to be controlled while it is in operation. Theprice of a suitable rheostat is a substantial part of the total cost ofan equipment, and

' this piece of apparatus is the source of most of the troubles thatarise in connection with motor drives for sewing machines. These andother disadvantages attending the employment of rheostats in connectionwith sewing machine equipments have long been recognized, and variousarrangements have been proposed to eliminate them by driving the motorscontinuously and bringing them into operative relation to the movingelements of the sewing machine whenever it isdesired that the latter bedriven.

In some of the arrangements that have been proposed for this purpose,the motors are fixed upon the tables of the sewing machines andconnected to friction wheels which are adapted to be swung intoengagement with the hand wheels of the machines whenever it is desiredto operate the latter. These arrangements, however, require the use ofextra members, and in some cases, owing to the movement of the swingingmembers upon which the friction wheels are carried, there is a change inthe tension of the driving belt. Arrangements have also been proposed inwhich the motors are pivotally mounted in such a manner that they may bemoved bodil to bring friction wheels mounted on the1r shafts intoengagement with the hand wheels of the machines whenever it is desiredthat the latter be operated, but these arrangements are open to theobjection that the speed at which the machlne is driven from the motordepends upon the pressure with which the friction wheel of the motor isheld against the hand wheel of the machine, and this pressure is subjectto considerable variation on account of changes in the force exerted bythe operator upon the treadle usually provided for controlling theposition of the motor. For'most rapid production, it is generallyconsidered that best results are obtained if machines are normallyoperated at a predetermined speed, and the operator is required toconform to. the speed of the machines. Such a practice cannot befollowed with any degree of certainty if the speed of the machine is asdirectly under the con trol of the operator as it is in the arrangementsmentioned above wherein slight variations in the effort expended by theoperator to hold the motor in driving relation to the machine result inconsiderable varia tions in the speed of the latter.

It is an object of this invention to provide a motor drive for sewingmachines in which the motor shall be held in operative relation to themachine by the weight of the motor, but may be conveniently taken out ofsuch relation whenever it is desired to stop the machine. Thearrangement therefore provides that under normal conditions of operationthe motor will be held in operative relation to the driving wheel of themachine in such a manner that the speed at which the machine is drivenshall be of a predetermined amount and will not be subject to variationsinthe effort expended by the operator as are prior arrangements of thisgeneral character. At the same time the arrangement permits the operatorto change the speed of the machine from time to time as may be required,but this regulation necessitates a special act on the part of theoperator which will not naturally be performed under normal conditionsof operation.

In accordance with the invention the mo tor is pivoted adjacent a wheelor pulley of the machine in such a manner that it may be oscillated tobe thrown into or withdrawn from operative relation with the wheel.Power may be transmitted from the motor to the machine by means of afriction pulley -on the shaft of the motor which is brought intoengagement with the hand wheel of the machine by allowing the motor tofall toward the machine, or a pulley on the shaft of the motor may beconnected by a belt to a driving pulley on the shaft of the machine, inwhich case the motor will be arranged to fall away from the machine toapply tension to the driving belt. For most conventient operation theposition of the motor should be under the control of a foot of theoperator in order that his hands may be free for manipulating the work.This is accomplished by providing a treadle having a flexible orlost-motion connection to the motor and which is normally actuated by aspring to swing the motor in such a manner as to disengage the frictionpulle from the hand wheel or slacken the driving belt, as the case maybe. When the effect .of the spring is overcome by pressure upon thetreadle, the motor will swing by gravity intoposition to transmit powerto the machine, and preferably the arrangement is such that the normalmovement imparted to the treadle will be sufficient to slacken theflexible connection so that the motor isiheld in operative relation tothe wheel of the machine by its own weight. The arrangement does,however, permit the speed of the machine to be controlled, for if thetreadle is not pressed downwardly to its full extent, the flexibleconnection will remain taut and balance the weight of the motor, so thatthe pressure with which its friction pulley is held against the handwheel of the machine will be lessened, or in case a belt drive isemployed, the effect of the weight of the motor in producing belttension will be partly overcome. In either case there v will be someslip in the driving connections, which will result in decreased speed ofthe machine. The natural condition of operation will be such that theoperator will find it most convenient to hold the treadle completelydepressed so as to release the flexible connection sufficiently to freethe motor and permit it to be held in operative relation with themachine by its own weight. It will be somewhat more tedious for theoperator to hold the treadle in partially depressed condition to producea slower speed of the ma chine.

The particular nature of the invention, as well as other objects andadvantages thereof, will appear more clearly from a description ofcertain preferred embodiments as illustrated in the accompanyingdrawings, in which y a Figure 1 is an end elevation of a sewing machineshowing the motor arranged for a friction drive;

Fig. 2 is an elevation of the apparatus viewed from the oppositedirection and with part of the frame of the machine broken awa Fig 3 isa side elevation of the frame of the machine with the device in placethereon Fi 4 is a detailed view in section along the line 4-4 of Fig. 3;and a Fig. 5 is an'end elevation showing the device arranged for a beltdrive.

The sewing machine illustrated somewhat diagrammatically in thedrawings, comprises a table 10 carried upon standards 11 and serving asa support for the frame 12 which comprises a vertical portion and ahorizontal portion at the outer end of which there is a head 13 withinwhich the mechanism for reciprocating the needle is mounted, this mecanism being driven by a shaft carrying the usual belt pulley 14 and handwheel 15. Mounted adjacent the hand wheel is an electric motor 16 whichas shown herein is carried upon a bracket like that disclosed in mycopending application, Serial No. 343,215, filed Dec. 8, 1919, but itwill be understood that the motor-may be supported adjacent the machinewheel in any other suitable manner.

The supporting bracket shown herein comprises a member 17 having at itsinner end upper and lower extensions 18 and 19,-respectively, adapted tofit over the top and bottom of the horizontal arm of the frame 12. Thesupporting member is bent outwardly as indicated in Figs. 1 and 2toclear the machine wheel and bring the motor in proper relation to thiswheel. In a supporting member constructed as above described,

the weight of the motor upon the end of the member will produce aturning moment which will be opposed by the engagement of the upper andlower extensions with the frame so that the member may be held in placeupon the frame without any otherment or dislodgment due to the vibrationof the motor or from any other cause. This auxiliary supporting memberconsists of a strip 0 metal or other suitable material having a fiatupper portion adapted to be seated upon the top of the machine frame andprovided with apertures through any one of which the usual spool spindle21 may be passed to hold the supporting member more securely in placeupon the frame. The depending portion of the strip is turned upwardly toform a hook within which the main supporting member is seated as shownmost clearly in Fig. 3.

The outer end of the supporting member 17 is bent at right angles toform an ear 22. Another ear 23 may be formed by cutting a portion of thesupporting member 17 and bending it at right angles. The ears carry apin 24 which passes through lugs associated with the motor casing.Placed upon the pin 24 between the motor lugs is a split clamp 25 whichserves to hold the motor in proper position longitudinally of thebracket.

In the arrangement shown in Figs. 1, 2 and 3, the shaft of the motor isprovided with a friction pulley 26 adapted to be held in engagement withthe hand wheel 15 of the machine by the weight of the motor, it beingunderstood that the supporting bracket is so constructed as to bring thepivot pin 24 in proper relation to the Wheel of the machine to permitthe motor to fall into operative relation to the wheel of the machine asshown most clearly in Fig. 1.

For the purpose of withdrawing the motor from operative relation to thewheel of the machine, there is provided a treadle 27 which may be placedin convenient position to be reached by the operators foot. A flexibleconnection 28 is attached at one end to the treadle and at the other endto a link 29 adapted to be secured to a lug 30 projecting from the motorcasing. Preferably the flexible connection 28 should be adjustablyattached to the link 29 as by means of a clamp 31, or other suitabledevice. Beneath the treadle is a spring 32 which normally raises thetreadle and through the connection 28 lifts the motor out of engagementwith the machine wheel, as indicated in Fig. 2. It is intended that theelements of the apparatus shall be so arranged that when the treadle isdepressed to its maximum extent the flexible connection 28 will becomeslack enough to permit the friction pulley of the motor to be held inengagement with the wheel of the machine by the weight of themotor, inwhich case the motor shaft and the pivot pin 24 will-lie upon a line A..

l/Vith the arrangement described above a sudden release of the treadlemight cause the motor to be thrown over to the other side of its pivot,whereas it should move only as far as indicated by the line B, in orderthat it may fall into engagement with the machine wheel when-the treadleis again depressed. In order to prevent any overthrow of the motor, theear 22 may be provided with an aperture 33 within which may be inserteda pin 34 to engage the corresponding lug of the motor and act as a stopfor the latter.

In some cases it may be desirable to employ a belt drive between themotor and the sewing machine, and in order that the device shall possessthe greatest range of utility provision for such a drive is 'made. Whena belt drive is employed the motor should be arranged to fall away fromthe wheel of the machine as shown in Fig. 5. It is therefore necessaryto attach the con nection leading to the treadle to the other side ofthe motor. For this purpose I provide a lug 35 corresponding to lug. 30but arranged upon the otherside of the pivot lugs of the motor. Byremoving the stop pin 34 the motor may fall away from the machine and beoperatively connected to the latter by a belt 36 passing over the pulleyl4 and the friction pulley 26 on the motor shaft. When such a change ismade it is necessary to shift the motor lengthwise of the pivot pin 24to bring the pulley on its shaft into alinement with the pulley 14. Thismay be done b changing the position of'the clamp 25. ith the apparatusarranged in Fig. 5, the spring 32 acting upon the treadle tends to swingthe motor toward the machine and slacken the belt sufficiently toprevent it from transmitting any power from the motor to the machine.

s in the case of the frictiondrive arrangement, means should be providedfor preventing the motor from being thrown over its pivot point. Forthis purpose the bracket ear 22 may be provided with a second hole 37into which the pivot pin 34 may be inserted to be engaged by one of thepivot lugs of the motor and limit the inward movement of the latter.When the treadle is depressed into the dotted line position of Fig.

ditions the flexible connection will be sufficiently slack so that thebelt tension produced by the weight of the motor will not be lessened bythe opposing effect of the spring 32. The motor will thus be free -todrive the machine at the predetermined speed regarded as suitable formost eflicient operation. In case it is desired to lessen the speed, thetreadle will be lifted sufficiently. to take up the slack in theflexible connection and then pull the latter enough to partiallyovercome the effect of the weight of the motor upon the tension of thebelt. There will thus be produced between the belt and the pulleys towhich it is connected, a certain amount of slip which will result in adecreased speed of operation of the machine without changing the speedof the motor by means of a rheostat or similar device.

The invention thus provides a motor drive for sewing machines which isof simple construction and eliminates the use of delicate and expensiveinstruments such as rheostats for controlling the speed of the motor. Atthe same time the arrangement is one that under normal conditions ofoperation insures that the sewing machine shall be driven at maximumspeed so that the efliciency of the operator is not lessened. It is,however, possible to produce changes in the speed of the machine byshifting the position of the motor, but such changes require that theoperator hold the treadle in an intermediate position which is not onlyless comfortable,

ut renders it more difiicult to maintain a 5 constant speed of themachine than when the treadle is in fully depressed position, which isin the nature of a stop position, and may be maintained by the operatorwith compara tivcly little effort. In other words, the usual conditionof the machine will be either one in which the driving motor is heldentirely out of operative relation to the machine by the spring actingupon the treadle, or one in which the motor is held in operativerelation to the machine by its weight independently of the spring, butit is possible to producea third condition in which the motor is held inoperative relation under the bal anced effect of its weight and theforce ex erted by the spring.

While certain preferred embodiments of the invention have been shown anddescribed, it will be understood that various changes in the details ofconstruction may be made without departing from the principle of theinvention as defined in the appended claims.

I claim 1. In a sewing machine provided with a r driving wheel, thecombination of a pivotally mounted motor adapted to be held in operativerelation to the wheel of the ma-. chine by its own weight, and means forantomatically lifting the motor out of operative relation to the wheelof the machine movable member, means for actuating the movablemember tomove the motor out of -operative relation to the driving wheel of themachine and adapted to be overcome by the operator to release theconnection to permit the motor to be held in operative relation to thedriving wheel of the'machine by its own weight.

3. In a sewing machine provided with a driving wheel, the combination ofa supporting member, a motor pivotally mounted on the supporting member,a movable member, a flexible connection between the motor and themovable member, means for actuating the movable member to move the motorout of operative relation to the driving wheel of the machine andadapted to be overcome by the operator 'to slacken the flexibleconnection sufliciently to permit the motor to be held in operativerelation to the driving wheel of the machine by its own weightindependently of the effect of the actuating means.

4. In a sewing machine provided with a driving wheel and a motor mountedto swin about a pivot displaced from its center 0 gravity, thecombination of means for controlling the position of the motor,comprising a spring-pressed treadle and a connection between the treadleand the motor to permit the motor to be lowered into operative relationto the wheel of the machine by pressure applied to the treadle toovercome the effect, of the spring.

5. In a sewing machine provided with a shaft having a driving wheelthereonand a pivotally mounted motor adapted to swing about an axisparallel tothe shaft of the machine, the combination of means forcontrolling the position of the motor, comprising a spring-pressedtreadle and a lost motion connection between the treadle and the motoradapted to permit the weight of the motor to hold it in operativerelation to the driving wheel of the machine independently of the effectof the spring when the treadle is actuated in a direction to overcomethe efiect of the spring upon the connection.

6. In a sewing machine provided with a driving wheel, the combination ofa supporting member, a motor pivotally mounted on the supporting member,a treadle, a spring for actuating the treadle, and means by which a pullmay be exerted upon the motor to lift it out of operative relation tothe wheelof the machine when the treadle is moved in one direction bythe spring and which will allow the motor to fal into operative relationto the wheel of the machine when the treadle is moved in the oppositedirection.

7 In a sewing machineprovided with a driving wheel and a pivotallymounted motor, the combination of a flexible member connected at one endto the motor and a spring-pressed treadle to which the other end of theflexible member is connected and adapted when in one extreme position tohold the motor out of operativerelation to the machine wheel, and whenin another extreme position to release the flexible member sufficientlyto permit the motor to remain in operative relation to the wheel of themachine under the influence of its own weight and independent of thelifting effect of the spring.

8. In a sewing machine provided with a driving wheel, the combination ofa supporting member, a motor pivotally mounted on the supporting memberin such a manner that it may fall toward or away from the wheel ofthemachine, a swinging member, a flexible member having one end connectedto the swinging member and adapted to be selectively connected at itsother-end to the motoron opposite sides of the pivot swinging mem 9. Ina sewing machine provided with a driving wheel, the combination of asupporting member adapted to be attached to the frame of the machine andprovided at its outer end with a pivot, a motor mounted upon the pivot,a treadle, a flexible connection having one end attached to the treadle,means by which the other end of the flexible connection may beselectively attached to the motor on either side of the pivot, a springfor actuating the treadle to swing the motor about its pivot, and a stopmem-.

ber associated with the supporting member and adapted to be selectivelyarranged on the side of the motor ivot corresponding to that which theflexi le member is connected, to limit the movemnt of the motor when 1tis swung by the spring.-

10. In arsewin machine provided with a frame, a hand w eel and a beltpulley the combination of a supporting member adapted to be attached tothe frame of the machine, a motor provided with a shaft adapted toreceive a power transmitting ulle said motor being pivotally and sl idaby mounted upon the supporting member in such a manner that it may falltoward or away from the wheel of the machine, means for adjusting theposition of the motor longitudinally of the supportin member so that thepower transmitting pul ey upon the shaft of the motor may be selectivelyalined with thehand'wheel and the belt pulley of the machine, a swingingmember, a flexible member havin one end connected to the Eer and adaptedto be selectively connected at its other end to the motor on oppositesides of the pivot of the motor, and means for actuating the swingingmember to rotate the motor in a direction opposite to that in which. itwould swing about its ivot under the influence of its weight, sairfmeans being adapted to be overcome by the operator to release theflexible member to permit the motor to' fall toward or away from themachine depending upon the point to which the flexible member isconnected to the motor.

11. In a sewing machine provided with a driving wheel, the combinationof a pivotally mounted motor adapted to be held in o erative relation tothe wheel of the ma- 0 ine' by its own weight, and a sprin forovercoming the weight of the motor w ereby it may be lifted out ofoperative relation to the wheel, said spring being adapted to beovercome by the operator to permit} the motor to be held in o erativerelation to the machine independent y of the lifting effeet of thespring.

12. Driving mechanism for a sewing machine comprising the combination ofa motor held in operative relation to the machine by the action ofapredetermined force, means orposing this force normally nullifying its eect and holding the motor in inoperative position, andlmeans independentof the. motor for counteracting this opposin means and permitting thepredetermine force to move the motor into operative position.

13. Driving mechanism for a sewing machine comprising the combination ofa motor desi ned to be held in operative relation to t e machine by itsown weight lifting means normally holding the motor 1n inoperativeposition, and means independent 0 the motor for counteracting the effectof the lifting means and permittlng the motor to fall into operativeposition.

In testimony whereof I aflix my signature.

' HYMAN. MAIMIN.

